POST /api/v1/webhooks/agent-release triggers all connected agents
to self-update via their existing WebSocket channels. Authenticated
with a shared secret (AGENT_WEBHOOK_SECRET env var).
- Add ReleaseChecker.invalidate_cache/0 for fresh GitHub fetch
- Add Agents.list_updatable_agents/0 (enabled + seen < 10min)
- Add Agents.broadcast_mass_update/0 orchestration function
- Add WebhookAuth plug with timing-safe secret comparison
- Add AgentReleaseWebhookController with :webhook pipeline
- Configure AGENT_WEBHOOK_SECRET in dev/test/runtime configs
